Want to make a simple turtle shell call

[blackmagic]

I found an old turtle shell off a burn last year.  I would like to make a simple call with it.  It still has the bottom piece.  I have some slate from an old hobby chalkboard.  Where should I start?
Thanks, I searched the forum here and came up blank.

[handcannon]

http://www.fieldandstream.com/node/57463

http://www.missouriwhitetails.com/forums/viewthread.php?tid=84993

[smurf]

Just be carefull where you are from or where you send the call.  In Missouri it is illegal to own the shell of an alligator snapping turtle.  I have found several that would have made gret calls but had to leave them alone to stay out of trouble. 

[blackmagic]

Thanks.  It's OK, here in FL.  just a little box turtle.  I've actually put it off and am making one out of a scallop shell from scallopping last summer.